2001 Ford Taurus idels low and stalls sometimes when stopping at a stop light

Sometime this will happen if the throttle blade idle hole gets plugged with carbon. if you take off the air inlet tube off the throttle body and look into the throttle body you will see a round looking flat disk , you will see a small hole in it .about the size of a stir stick straw .this hole gets plugged with carbon and will effect the idle.it calibrated to let the right amount of air in the engine @ idle.if you clean this there is a good chance this will fix your problem . be careful what cleaner you use as some of the throttle blades are coated with a Teflon coating(local parts store will have the proper throttle body cleaner for these ford throttle bodies )